Climate and monthly weather forecast
Sullivan's Island, SC

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Weather in January

January, the same as December, in Sullivan's Island, South Carolina, is another mild winter month, with an average temperature ranging between max 57°F (13.9°C) and min 45.5°F (7.5°C). January is the coldest month, with the temperature often reaching an average high of 57°F (13.9°C) and an average low of 45.5°F (7.5°C). Weather in January »

Weather in February

The last month of the winter, February, is another refreshing month in Sullivan's Island, South Carolina, with an average temperature fluctuating between 48.7°F (9.3°C) and 59.9°F (15.5°C). February commences with an average high-temperature of a still moderate 59.9°F (15.5°C), showing little deviation from January's 57°F (13.9°C). Weather in February »

Weather in March

The first month of the spring, March, is an enjoyable month in Sullivan's Island, South Carolina, with an average temperature varying between 64.4°F (18°C) and 53.6°F (12°C). March experiences an average high-temperature of an enjoyable 64.4°F (18°C), barely different from February's 59.9°F (15.5°C). Weather in March »

Weather in April

April in Sullivan's Island, South Carolina, is an agreeable spring month, with temperature in the range of an average high of 71.8°F (22.1°C) and an average low of 61.3°F (16.3°C). Sullivan's Island in April experiences a slight uptick in the average high-temperature, adjusting from March's enjoyable 64.4°F (18°C) to an agreeable 71.8°F (22.1°C). Weather in April »

Weather in May

The last month of the spring, May, is a warm month in Sullivan's Island, South Carolina, with temperature in the range of an average high of 78.1°F (25.6°C) and an average low of 68.7°F (20.4°C). Sullivan's Island's weather shows a minor temperature rise with the arrival of May, moving from a pleasant 71.8°F (22.1°C) in April to a warm 78.1°F (25.6°C). Weather in May »

Weather in June

June, the first month of the summer in Sullivan's Island, is also a moderately hot month, with an average temperature varying between 75.4°F (24.1°C) and 84.6°F (29.2°C). Sullivan's Island observes a slight ascent in average high-temperatures during June, adjusting from 78.1°F (25.6°C) in May to a still moderately hot 84.6°F (29.2°C). Weather in June »

Weather in July

July is a tropical summer month in Sullivan's Island, South Carolina, with temperature in the range of an average low of 78.3°F (25.7°C) and an average high of 86.5°F (30.3°C). In Sullivan's Island, the month of July registers the highest temperatures, averaging 86.5°F (30.3°C) at the peak and 78.3°F (25.7°C) at the lowest. July's average heat index is appraised at a very hot 98.6°F (37°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Sullivan's Island, South Carolina, with an average temperature ranging between min 78.1°F (25.6°C) and max 85.8°F (29.9°C). The average high-temperature is a moderately hot 85.8°F (29.9°C) in August, hardly different from the 86.5°F (30.3°C) recorded in July. Weather in August »

Weather in September

The first month of the autumn, September, is also a moderately hot month in Sullivan's Island, South Carolina, with an average temperature ranging between min 74.3°F (23.5°C) and max 82.9°F (28.3°C). As August turns into September, the average high-temperatures rest at a still warm 82.9°F (28.3°C), showing a minor variation from the prior month. Weather in September »

Weather in October

October, like September, in Sullivan's Island, South Carolina, is another warm autumn month, with an average temperature fluctuating between 64.9°F (18.3°C) and 75.2°F (24°C). Start of October brings a slight shift in the average high-temperature, dipping a bit from September's 82.9°F (28.3°C) to a still moderately hot 75.2°F (24°C). Weather in October »

Weather in November

November, the last month of the autumn in Sullivan's Island, is another comfortable month, with temperature in the range of an average low of 54.9°F (12.7°C) and an average high of 65.7°F (18.7°C). With November's onset, the average high-temperature recedes from October's warm 75.2°F (24°C) to an enjoyable 65.7°F (18.7°C). Weather in November »

Weather in December

The first month of the winter, December, is also an enjoyable month in Sullivan's Island, South Carolina, with an average temperature varying between 50.4°F (10.2°C) and 61°F (16.1°C). The advent of December reveals an average high-temperature of a still enjoyable 61°F (16.1°C), showing minimal difference from the prior month. Weather in December »

Frequently asked questions

What time of the year is the coldest?

The lowest temperatures are recorded in January, with averages reaching a high of 57°F (13.9°C) and a low of 45.5°F (7.5°C).

What are the least humid months?

The months with the lowest humidity are January and March, with an average relative humidity of 73%.

What is the driest month?

January is the month with the least rainfall. Rain falls for 9.7 days and accumulates 1.42" (36mm) of precipitation.

How much does it rain?

In Sullivan's Island, during the entire year, the rain falls for 182 days and collects up to 45.55" (1157mm) of precipitation.

When does it snow?

January and February are months with snowfall in Sullivan's Island.

What is the snowiest month?

January has the most snowfall days of the year in Sullivan's Island. Snow falls for 0.3 days.

How many days does it snow?

Throughout the year, there are 0.4 snowfall days.

What is the month with the lowest UV index?

The month with the lowest UV index is January, with an average maximum UV index of 3.

When it does not snow in Sullivan's Island?

In Sullivan's Island, snow does not fall in March through December.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.

What is the month with the highest UV index?

The months with the highest UV index are May through August, with an average maximum UV index of 7.

When are the longest days?

The month with the longest days is June, with an average of 14h and 18min of daylight.

What time of the year is the hottest in Sullivan's Island?

In Sullivan's Island, July is identified by the average highest temperatures, reaching a peak of 86.5°F (30.3°C) and a low of 78.3°F (25.7°C).

What month has the most sunshine?

The month with the most sunshine is July, with an average of 11h of sunshine.

What is the rainiest month?

August is the month with the most rainfall. Rain falls for 25.9 days and accumulates 8.23" (209mm) of precipitation.

What is the most humid month?

The most humid month in Sullivan's Island is December, with an average relative humidity of 78%.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 10h and 0min of daylight.

What is the month with the least sunshine?

The month with the least sunshine is December, with an average of 5.7h of sunshine.

Average temperature
Sullivan's Island, SC

Average temperature - Sullivan

The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is January (57°F).

The month with the highest average low temperature is July (78.3°F).
The coldest month (with the lowest average low temperature) is January (45.5°F).

Average pressure
Sullivan's Island, SC

Average pressure - Sullivan

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).

Average wind speed
Sullivan's Island, SC

Average wind speed - Sullivan

The windiest months (with the highest average wind speed) are March and April (10.3mph).
The calmest month (with the lowest average wind speed) is August (8.4mph).

Average humidity
Sullivan's Island, SC

Average humidity - Sullivan

The month with the highest relative humidity is December (78%).
The months with the lowest relative humidity are January and March (73%).

Average rainfall
Sullivan's Island, SC

Average rainfall - Sullivan

The wettest month (with the highest rainfall) is August (8.23").
The driest month (with the least rainfall) is January (1.42").

Average rainfall days
Sullivan's Island, SC

Average rainfall days - Sullivan

The month with the highest number of rainy days is August (25.9 days).
The month with the least rainy days is November (8.5 days).

Average snowfall days
Sullivan's Island, SC

Average snowfall days - Sullivan

The month with the highest number of snowfall days is January (0.3 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October, November and December (0 days).

Average daylight / Average sunshine
Sullivan's Island, SC

Average daylight / Average sunshine - Sullivan

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

The month with the most sunshine is July (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

Average sunshine days
Sullivan's Island, SC

Average sunshine days - Sullivan

The month with the most sunshine days is January (19.3 days).
The month with the least sunshine days is August (2.8 days).

Average UV index
Sullivan's Island, SC

Average UV index - Sullivan

The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is January (UV index 3).

Average visibility
Sullivan's Island, SC

Average visibility - Sullivan

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Sullivan's Island, South Carolina, USA

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